Just two days ago, it was believed that Google+ had roughly 18 million users. We can now up that number to 20 million.

Although Ancestry.com founder Paul Allen hypothesized using his own formula that Google+ had 18 million users by earlier this week, comScore has had at least 20 million unique visitors since the site debuted three weeks ago.

"I've never seen anything grow this quickly," said Andrew Lipsman, vice president of industry analysis at comScore. The only other site that has accumulated as many new visitors in a short period of time is Twitter in 2009, he said, "but that happened over several months."

comScore also broke down those users by country, finding that the majority are from the United States with 5.31 million, followed by India at 2.85 million and the United Kingdom at just under one million visitors.

Additionally, Google+ is about to get even bigger (and even more competitive with Facebook) with the debut of a new feature: Games.

AllThingsD reports that "Google will take less than a 30 percent cut of the revenues, which will break the industry standard created over the past few years by both Facebook and Apple."

A launch date for the platform hasn't been set yet, but it is expected to debut soon - possibly with integrated in-app payments. Zynga is also reported to be likely involved with Google's next venture. So now there will be yet another social network where we cannot escape invitations to Farmville. Maybe Google+ won't be any better than Facebook after all.